The BiDi Screen is an example of a new type of I/O device that possesses the ability to both capture images and display them. This thin, bidirectional screen extends the latest trend in LCD devices, which has seen the incorporation of photo-diodes into every display pixel. Using a novel optical masking technique developed at the Media Lab, the BiDi Screen can capture lightfield-like quantities, unlocking a wide array of applications from 3-D gesture interaction with CE devices, to seamless video communication.